Standa manufactures Fresnel Rhombs and mounts for them. 14FR is a combination of a rhomb with a mount (see drawings). Fresnel Rhombs are made of BK7 crown glass or UV grade fused silica. A Single Fresnel Rhomb produces a phase shift of 90° (l/4) due to total internal reflections at two surfaces. A Double Fresnel Rhomb produces a phase shift of 180° (l/2) between the components of light polarized perpendicular and parallel to the plane of incidence. It consists of two optically contacted (or air spaced) single Fresnel l/4 Rhombs. The retardation varies only slightly over a relatively wide range of wavelengths. Fresnel Rhombs mounts are cylindrical in shape. The end faces of a Fresnel retarder are adjusted orthogonal to the axis of rotation. The clear aperture of the mount is 10 mm. There are several ways to mount the 10FR Fresnel rhomb retarder: - on any adjustable unit (e.g. a stage) by the M6 and M4 tapped holes - to our Polarizer Holder as 5PH50, 5PH51 or other compatible unit using the M27x1 thread
